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New developments in the manufacture and utilization of multinutrient blocks - Short communications


The increasing popularity of multinutrient blocks
What is new in the manufacturing?
New results on animals
Field experience
Conclusions
Bibliography

R. Sansoucy

The author is Senior Officer (Feed Resources), Animal Production Service, Animal Production and Health Division, FAO, Rome, Italy.

The increasing popularity of multinutrient blocks

Since the early 1980s the manufacture and utilization of multinutrient blocks as supplements for ruminant animals have increased considerably in developing countries. The work of Leng (1983) in Australia and India has been a catalyst for the promotion of this technology. After the adoption of a new and simple technology based on a cold process that needs no or little equipment (Sansoucy, 1986), the blocks have been developed in more than 60 countries on all continents. The manufacture and use of blocks were reviewed recently in international meetings (IAEA, 1991; Cardozo and Birbe, 1994) and their potential and constraints identified (Rajkomar, 1991). The degree of adoption at farm level varies much with local conditions : characteristics of the basal diet, availability and cost of different ingredients, production systems, end-product prices and marketing capacity.

What is new in the manufacturing?

At the artisanal level, the hot process has practically been abandoned for the benefits of the cold process, which does not need sophisticated equipment (such as a double-jacket boiler) nor much energy (no heating). When the cost of labour is low and the quantities of blocks required in the region are modest, or when they are made on the farm, the blocks are made by hand, otherwise the concrete mixer is the most commonly used equipment for mixing the ingredients.

New binders have been tried. In particular, ordinary clay used at the level of 20 percent in Cambodia (Kayouli, 1994a) and in the United Republic of Tanzania (Preston, 1993) has proved to be efficient for making blocks that include 20 percent diluted molasses (Brix 55) or the scums from artisan production of syrup (Brix 20 to 23). The other ingredients were: 35 percent bran, 5 percent cement, 5 percent lime, 7.5 percent urea and 7.5 percent salt. Clay is first mixed with water (50 percent of the clay's dry weight or 25 percent of its wet weight) and then the lime, cement and salt are added. The urea is mixed with molasses and then added to the clay and other components.

Molasses may not always be available or it may be too expensive in certain countries or regions. For this reason, alternatives have been studied in order to manufacture blocks without or with little - about 10 percent-molasses (Hassoun and Bâ, 1991). In this case, urea and cement must be diluted in water. Bran is mixed in at the end, and additional water (30 to 60 percent of the total weight of the dry ingredients) is necessary as all ingredients are dry or have low moisture content (Table 1).

Scums (filter muds) from the sugar industry, at the level of 40 percent, have also been used to replace molasses in blocks in Trinidad and Tobago (Sansoucy and Neckles, 1992, unpublished data) and Grenada (Pérez, 1994). This allows for a substantial reduction in production costs as the scums can usually be obtained from the sugar factory free of charge.

The manufacture of multinutrient miniblocks for rabbits was first suggested by Rena Pérez (1986, personal communication), and then by Cheeke and Raharjo (1988). These blocks are designed to replace the pellets that are commonly used in developed countries, but which are too costly to be manufactured in most developing countries (Pérez, 1990). They usually do not contain urea and can be formulated to include the forage component of the diet, thus making a complete feed (Table 2). The level of intake may be controlled by varying the hardness of the blocks by using various proportions of cement (Amici and Finzi, 1994).

New results on animals

The positive effects of supplementing ruminants fed on unbalanced roughages with blocks for the production of meat and/or milk have been well documented (Sansoucy, Aarts and Leng, 1988; Leng et al., 1991). The most recent results shall be presented here so as not to overlap previous observations.

Better knowledge of the effect of blocks on animals

Ricca and Combellas (1993) have shown that the blocks have a positive effect on the growth of animals when forage or grazing is sufficiently available, for example, at the beginning of the dry season, but they have no effect when the basal diet is limited in quantity.

For some time, it has been apparent that the urea contained in the blocks has allowed for a considerable increase in the ammonia concentration of the rumen liquor, thus improving the rumen ecosystem and favouring microbial development. It now seems that probably other microbial growth factors are also provided at the same time (Hendratno, Nolan and Leng, 1991), particularly sulphur and trace elements contained in molasses.

1 - Composition of some multinutrient blocks without molasses - Composition de blocs multinutritionnels sans mélasse - Composición de algunos bloques multinutricionales sin melaza

Ingredients

Block A1

Block B2

Block C3

Block D4


(percentage)

Urea

10

10

10

10

Salt

10

10

5

10

Cement/lime

15

5

10

10

Clay

-

15

-

-

Filter mud

-

-

40

-

Coconut meal

-

-

17.5

-

Olive cake

-

-

-

35

Bran

65

60

17.5

35

Additional water

60

30-50

-

30

1 Hassoun & Bâ, 1990.
2 Kayouli, 1994.
3 Sansoucy & Neckles, 1992, unpublished data.
4 Hadjipanayiotou et al., 1993.

2 - Composition of some block formulas for rabbits - Composition de quelques miniblocs pour lapin - Composición de las fórmulas de algunos bloques para conejos

Ingredients

Block A1

Block B2

Block C3

Block D4


(percentage)

Molasses

43

45

50

50.8

Rice/wheat bran

-

-

13

17.5

Cassava leaf meal

-

-

10

-

Soybean seed/meal

-

25

-

-

Min-Vit pre-mix

10

10

-

-

Lime/cement

7

8-10

5

3.2

Fibre source/leaves

10

10-12

20

17.2

Salt

-

-

2

-

Broken rice

-

-

-

11.3

1,2 Pérez, 1990.
3 Dinh Van Binh, Bui Van Chinh & Preston, 1991.
4 Amici & Finzi, 1994.

Reproductive animals

More information has been obtained on the effect of blocks on reproductive factors. For example, in Colombia, African hair ewes fed ad lib on cane tops and restricted Gliricidia foliage and supplemented with blocks containing 10 percent urea and 50 percent molasses initiated their ovarian activity sooner (76 percent of those supplemented within 60 days versus 32 percent of those not supplemented) and had a shorter interval between parturition and conception (less than 90 days, 70 percent of those supplemented versus 44 percent of those not supplemented) (Vargas and Rivera, 1994). The annual mortality rate was also reduced for ewes (6 percent supplemented versus 20 percent not supplemented) as well as for lambs at weaning (8 percent supplemented versus 32 percent not supplemented).

In Indonesia, Hendratno, Nolan and Leng (1991) also found that blocks had positive effects on the reproductive parameters of dairy goats. In particular, blocks increased the birth weight and liveweight gain of kids by 15 percent and decreased the time between pregnancies by 5.3 percent. As reproduction rates are low in many countries, it appears that one of the most beneficial effects of multinutrient blocks could be the improvement of herd reproduction parameters. In this context, adding phosphorus to the blocks would be useful.

Working animals

In Bangladesh, Saadullah (1991) observed that supplementation of urea-molasses blocks to draught cows fed a basal diet of rice straw increased feed intake, daily milk yield, lactation period and daily liveweight gain from calving to pregnancy diagnosis, as well as draught output.

Supplementation of working buffaloes fed a basal diet of rice straw and a certain amount of grass with blocks resulted in a significant improvement in their health and productivity in the Mekong Delta region of Viet Nam (Table 3). Buffaloes could plough approximately 20 percent more land at the beginning of the working period and up to 40 percent more after one month of work, since they worked at a higher speed and recovered faster from work. Weight loss was also reduced.

Blocks as carriers of anthelmintics for ruminants

More recently, blocks have also been used as an interesting carrier for anthelmintic medicines. In Fiji, India and Malaysia, in a project funded by the Australian Centre for International Agricultural Research (ACIAR), strategies for sustainable control of gastrointestinal parasites of ruminants using urea-molasses blocks were studied.

In Venezuela, for 68 days during summer, heifers weighing from 230 to 250 kg that were moderately infested by helminths and grazing on star grass and Brachiaria pasture received no block and no anthelmintic (TO); anthelmintic only (T1); or block (1 kg/day) + anthelmintic separately (T2) or anthelmintic included in block (T3) (Araque, 1994). The effect of the drug on the reduction of the infestation was similar, whatever the mode of administration, but the distribution of anthelmintics through the blocks was found to be more convenient. Furthermore, the growth rate was higher for animals receiving blocks (650 g/day versus 400 g/day).

Rabbits

Various experiments have recently been made to feed "miniblocks" or crumbs to rabbits. One big advantage, particularly for the small farmer, is that the miniblocks can be distributed on the ground, without the need for specialized feeders or forage racks and without wastage (Filippi, Amici & Machin, 1992) (Table 2). In Viet Nam, blocks containing 50 percent molasses have been successfully used as a partial substitute (30 to 60 percent) for cereal-based concentrates in diets based on elephant grass for rabbits in all phases of production (Dinh Van Binh, Bui Van Chinh and Preston, 1991). Although performances were slightly reduced, economic results were better. Inclusion of urea had no beneficial or harmful effect (Dinh Van Binh, Bui Van Chinh and Preston, 1991). Amici and Finzi (1994) compared the growth rates of rabbits fed on alfalfa alone, alfalfa plus blocks (about 40 to 50 percent of the dry-matter intake), and industrial pellets. Average daily gain of those receiving blocks was higher than those fed with alfalfa alone, but lower than those fed with pellets, between the ages of 37 and 75 days. At approximately 80 to 90 days, there was no difference between animals fed on blocks or pellets (average daily gain was 34 g).

3 - Changes in liveweight, physiological values and ploughing capacity of working buffaloes during wet season in Viet Nam - Evolution du poids vif, des valeurs physiologiques et de la capacité de labour des buffles de travail pendant la saison des pluies au Viet Nam - Cambios en el peso vivo, los valores fisiológicos y la capacidad para arar de los búfalos de trabajo durante la estación húmeda en Viet Nam

Criteria

Control

Cake-fed

Probability

Liveweight (kg)

At start

345.9

372.0

After 1 month

333.9

370.2

Change

-12.0

-1.8

<0.001

Ploughed area (m2/pair/day)

At start

1 919.2

2 243.0

After 1 month

1 508.4

2 141.2

Change

-410.8

-101.8

<0.001

Ploughing speed (m/min.)

At start

35.73

43.50

After 1 month

31.53

40.70

Change

-4.20

-2.80

<0.001

Recovery time (min.)

At start

13.7

11.9

After 1 month

16.1

12.7

Change

2.4

0.8

<0.05

Source: Thu et al., 1993.

Field experience

Considerable field experience with multinutrient blocks has been gained during recent years. Farmers' observations have been noted and their successes and failures have brought to light the most important factors for further development.

Blocks being prepared by hand in Cambodia - Préparation de blocs à la main au Cambodge - Preparación de bloques a mano en Camboya

A concrete mixer is ideal for mixing the ingredients - Une bétonneuse est idéale pour mélanger les ingrédients - Una hormigonera es ideal para mezclar los ingredientes

Farmers' observations

The following interesting observations made by farmers who were supplementing their animals' diets with multinutrient blocks were reported by Kayouli (1994a, 1994b):

· animals had a higher intake of fibrous feeds and consumed some forages that they had previously ignored because of their low palatability;

· similarly, when grazing they were less selective;

· they drank more water, which is probably the result of a higher intake of dry matter;

· they stopped licking the earth, walls, poles, etc. because of the correction of mineral deficiencies and/or higher level of nutrition;

· they looked healthier, their skin appearance improved and so did their body condition.

Factors of development

Although multinutrient blocks have become very popular, not all projects using them have been successful. Several factors influencing their success or failure have been observed:

· The blocks must only be used to solve practical problems encountered by farmers, for example, the lack of a nitrogen source when animals are fed on fibrous crop residues or poor-quality pastures. Blocks have no effect on animals already on good-quality pastures.

· The choice of target animals is important. It was generally expected that dairy cattle would be the obvious candidates. In some countries, however, farmers gave priority to draught animals since they are the main source of power in preparing the land for crops.

· The quality of the blocks must be consistent. If they are too soft, there may be risks of toxicity resulting from the high intake of urea. If they are too hard, the intake is too low to have any effect on the animals.

· It is necessary to ensure that good technical assistance is provided to the producer of blocks, especially in small units, which are the most common, and also to the user so that the blocks are utilized under the most favourable conditions.

· The blocks should be promoted within the framework of development projects for an adequate period of time, such as over several years.

· It may be necessary to assist small farmers with credit to purchase the blocks.

· Blocks must be easily accessible to the small farmer. Marketing is another important aspect that must be ensured.

· Finally, the cost/benefit ratio is a determining factor. The farmers must obtain financial benefits from their investment, which would depend upon the cost of the various ingredients as well as the price of the end-products (milk, meat, wool, work).

Goats eating multinutrient blocks - Chèvres mangeant des blocs multinutritionnels - Cabras comiendo bloques multinutricionales

Blocks can also be prepared for rabbits - On peut aussi préparer des blocs pour les lapins - También se pueden preparar bloques para conejos

A small farmer showing her homemade blocks in the Niger - Une petite exploitante nigérienne montre des blocs qu'elle a fabriqués elle-même - Una agricultora nigeriana mostrando bloques fabricados en la finca

Conclusions

The various studies recently undertaken in different parts of the world concerning the manufacture and utilization of multinutrient blocks have led to real progress in the technology and its use. The practicability of the cold process has been demonstrated. The feasibility of making blocks without molasses has opened up new possibilities for their use in more countries and regions. On-station experiments and on-farm observations have improved the available knowledge on the effects of blocks and the conditions necessary for their development.

Bibliography

Amici, A. & Finzi, A. 1994. Molasses blocks as supplementary feed for growing rabbits. (In preparation)

Araque, C.A. 1994. Resultados de investigación sobre bloques multinuticionales en Bovinos. In Cardozo y Birbe, 1994, p. 21-25.

Cardozo, A.F. & Birbe, B., eds. 1994. Bloques multinutricionales. Memorias de la primera conferencia internacional, Guanare, Venezuela, 29-31 July 1994, p. 119.

Cheeke, P.R. & Raharjo, C. 1988. Evaluación de forrajes tropicales y subproductos agrícolas como alimento para conejos. In T.R. Preston & M. Rosales, eds. Sistemas intensivos para la producción animal y de energía renovable con recursos tropicales Cali, Colombia, CIPAV. p. 33-42.

Dinh Van Binh, Bui Van Chinh & Preston, T.R. 1991. Molasses-urea blocks as supplements for rabbits. Livestock Res. Rural Dev., 3(2): 13-18.

Filippi, B.G., Amici, A. & Machin, D. 1992. Initial studies on the production and use of molasses blocks in the feeding of forage fed rabbits. J. Appl. Rabbit Res., 15: 1053-1057.

Hadjipanayiotou, M., Verhaeghe, L., Allen, M., Abd el-Rahman Kronfoleh, Al-Wadi, M., Amin, M., Naigm, T., El-Said, H. & Abdul Kader Al-Haress. 1993.I. Methodology of block making and different formulae tested in Syria. Livestock Res. Rural Dev., 5(3): 6-15.

Hassoun, P. & Bâ, A.A. 1991. Mise au point d'une technique de fabrication de blocs multinutritionnels sans mélasse. Livestock Res. Rural Dev., 2(2).

Hendratno, C., Nolan, J.V. & Leng, R.A. 1991. The importance of urea-molasses multinutrient blocks for ruminant production in Indonesia, p. 169. Vienna, IAEA.

IAEA. 1991. Proc. Int. Symp. Nucl. Related Tech. Anim. Prod. Health, Vienna, Austria, 15-19 April 1991, p. 115-169. Vienna, International Atomic Energy Agency.

Kayouli, C. 1994a. Rapport de mission, projet FAO/TCP/CMB/ 2254 "Plan d'urgence pour la sauvegarde de bétail au Cambodge", Cambodge, mars-avril 1994. pp. 50.

Kayouli, C. 1994b. Rapport de mission, projet FAO/PNUD/ NER/89/016 "Traitement à l'urée des fourrages grossiers", Niger, mai 1994. pp. 28.

Leng, R.A. 1983. The potential of solidified molasses-based blocks for the correction of multinutritional deficiencies in buffaloes and other ruminants fed low quality agro-industrial by-products. In The use of nuclear techniques to improve domestic buffalo production in Asia, p. 135-150. Vienna, Austria, International Atomic Energy Agency (IAEA).

Leng, R.A., Preston, T.R., Sansoucy, R. & George Kunju, P.J. 1991. Multinutrient blocks as a strategic supplement for ruminants. Wld Anim. Rev., 67: 11-19.

Pérez, R. 1990. Manual de crianza: conejos (p. 79). Ministerio del Azúcar, Havana, Cuba. 101 pp.

Pérez, R. 1994. First mission report. FAO/TCP/GRN/2351 project "Sugarcane and other local feed resources for feeding livestock", Grenada, March 1994, 15 pp.

Preston, T.R. 1993. Report of the first advisory mission. FAO/TCP/URT/2255 project "Increasing livestock production by making better use of available feed resources", United Republic of Tanzania, June 1993, 20 pp.

Rajkomar, B. 1991. The molasses block technology in Mauritius and the African perspective. Livestock Res. Rural Dev., 3(3): 52-62.

Ricca, R. & Combellas, J. 1993. Influence of multinutrient blocks on liveweight gain of young bulls grazing sorghum stubble. Livestock Res. Rural Dev., 5(3): 31-38.

Saadullah, M. 1991. The importance of urea-molasses blocks and bypass protein in animal production: the situation in Bangladesh, p. 145-156. Vienna, IAEA.

Sansoucy, R. 1986. The Sahel: manufacture of molasses-urea blocks. Wld Anim. Rev. 57: 40-48.

Sansoucy, R., Aarts, G. & Leng, R.A. 1988. Molasses-urea blocks as a multinutrient supplement for ruminants. In R. Sansoucy, G. Aarts & T.R. Preston, eds. Sugarcane as feed, p. 263-279. FAO Animal Production and Health Paper No. 72. Rome, FAO.

Thu, N., Dong, N., Hon, H. & Quac, V. 1993. Effect of molasses-urea cake on performance of growing and working local buffaloes and cattle. Livestock Res. Rural Dev., 5(1): 46-53.

Vargas, J.E. & Rivera, J.G. 1994. Efecto del bloque multinutricional sobre el comportamiento productivo en ovejas africanas. Livestock Res. Rural Dev., 6(2): 20.


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